II. Circulating needed materials:
1. How does O2 get in and out?

Starfish: The bumps on the sea star absorb oxygen

Pig: Breath in and out of their noses

Crayfish:Extract oxygen from the water using their gills
2. How is O2 and other materials moved throughout the body?

All the organisms move oxygen through their bodies using their blood. Crayfish have something called hemocyanin that stores oxygen and transports it where it needs to go. The hemocyanin causes the blood of the organism to turn blue. Pigs and starfish have something very similar to this but it is called hemoglobin the only big difference is that it has iron in it instead of copper and it causes the blood to be red.
3. Draw a diagram of the movement of O2 and other materials through this system (or take a picture and mark up the movement).

Screen_shot_2011-05-26_at_8.44.24_AM.png